ISL32455EIUZ-T - ±60V Fault Protected RS-485/RS-422 Transceiver | Renesas
MPN: ISL32455EIUZ-T ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.45 | $2.45 |
| 10 | $2.2 | $22.00 |
| 100 | $1.95 | $195.00 |
| 500 | $1.72 | $860.00 |
| 1,000 | $1.55 | $1,550.00 |
| 2,500 | $1.43 | $3,575.00 |
ISL32455EIUZ-T Overview
An RS-485/RS-422 transceiver is a differential line driver/receiver IC used for balanced multipoint or point-to-point communication over twisted-pair cabling, where robust noise immunity, long cable reach (typically up to 1200 m), and multi-drop bus capability are required. As part of the broader Interface IC > Driver/Receiver family, RS-485 transceivers are the de-facto standard for industrial fieldbus, building automation, motor control, and any application where signals must traverse electrically noisy environments or span tens to hundreds of metres.
Key differentiating specifications include ±60V overvoltage fault protection on the bus pins (driver outputs and receiver inputs), ±20V common-mode range that exceeds the TIA/EIA-485 minimum, ±15kV IEC 61000-4-2 ESD strike tolerance on the bus pins, and 1/8 unit load allowing up to 256 transceivers on a single bus. The cable-invert pin reverses the polarity of the differential driver outputs, simplifying field wiring fixes without board rework. Logic-side inputs are 3.3V/5V tolerant for direct MCU/FPGA interfacing.
The ISL32455E architecture combines a precision differential line driver, a wide-CMR differential receiver with hysteresis, internal ±60V TVS-like protection on the bus pins, and ESD clamp structures on both bus and logic pins. Hot-plug circuitry prevents latch-up and bus glitches when the device is inserted into a live bus, while a thermal-shutdown block protects the IC during sustained short-circuit events on the bus. Current-limiting on the driver outputs protects against wiring faults.
Typical applications include factory automation fieldbus (Modbus, Profibus), building automation (BACnet, LonWorks), solar inverter daisy-chains, motor drive encoder interfaces, and any industrial cable link exposed to large fault voltages from cross-wiring, ESD events, or switching transients. The half-duplex form factor is ideal where a single twisted pair carries both transmit and receive data.
When designing with this part, ensure the cable-invert pin is tied to a defined logic level (do not float) and that the bus is terminated at both ends with 120 Ω matching the cable characteristic impedance. Adequate PCB layout separation between the bus pins and sensitive analog traces is recommended to exploit the -15 kV ESD rating. The ISL32455EIUZ-T shares the ISL3245xE family footprint and pinout, enabling PCB reuse across the 50E/52E/53E/55E/57E/58E/59E variants.
This page synthesises distributor pricing, family-level cross-reference data, and practical bus-design notes not consolidated in the manufacturer datasheet.
Drop-in alternatives for ISL32455EIUZ-T — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
ISL32455EIUZ
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ISL32455EIUZ-T7A
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ISL32455EIUZ-T13
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ISL32457EIUZ-T
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SN65HVD75DR
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ISL32455EIUZ-T Specifications
| Device Type | Transceiver (RS-485/RS-422) |
| Protocol | RS-422, RS-485 |
| Number of Drivers/Receivers | 1/1 |
| Duplex | Half |
| Supply Voltage | 3.3 V to 5 V |
| Data Rate | 1 Mbps |
| Bus Fault Protection | ±60 V |
| Common-Mode Range | ±20 V |
| ESD Protection (Bus Pins) | ±15 kV |
| Unit Load | 1/8 unit load (up to 256 nodes) |
| Cable Invert Pin | Yes |
| Operating Temperature | -40 °C to +85 °C (Industrial) |
| Package | 8-pin MSOP (UZ) |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
ISL32455EIUZ-T Pin Configuration
| Pin 1 | RO — Receiver output (logic-level, referenced to VCC) |
| Pin 2 | RE — Receiver enable (active-low); tie low to enable RO |
| Pin 3 | DE — Driver enable (active-high); tie high to drive bus |
| Pin 4 | DI — Driver input (logic-level, referenced to VCC) |
| Pin 5 | GND — Ground reference for logic and bus |
| Pin 6 | A/Y — Non-inverting bus pin (cable-invert pin swaps A/Y polarity) |
| Pin 7 | B/Z — Inverting bus pin (cable-invert pin swaps B/Z polarity) |
| Pin 8 | VCC — Supply voltage, 3.0 V to 5.5 V |
Typical Applications
ISL32455EIUZ-T is suitable for 7 applications: Industrial Fieldbus (Modbus RTU), Building Automation (BACnet MS/TP), Solar Inverter Daisy-Chain Communication, Motor Drive Encoder Interface, Factory Automation Sensor Networks, Lighting Control (DALI / DMX over RS-485), Access Control / Card Reader Daisy Chain.
Industrial Fieldbus (Modbus RTU)
The ISL32455EIUZ-T is a strong fit for Modbus RTU and similar RS-485 industrial fieldbus segments because its 1 Mbps signalling comfortably exceeds the 115.2 kbps maximum specified by Modbus RTU while leaving margin for long cable runs. The integrated ±60 V fault protection directly tolerates miswiring to 24 VAC/DC control wiring that is common on factory floors. The 1/8 unit load allows dense multi-drop sensor networks - up to 256 nodes on a single bus - eliminating repeaters. Place the device at each node with a 120 Ω termination resistor at the bus ends, a 4.7 nF bus-pin bypass to ground, and short stub lengths to limit reflections.
Recommended
Building Automation (BACnet MS/TP)
The ISL32455EIUZ-T's ±15 kV IEC 61000-4-2 ESD on the bus pins directly targets the harsh electrical environment of building automation panels, where HVAC contactors and motor starters generate large transient events. Its 1 Mbps data rate supports BACnet MS/TP up to the highest standard baud rate, while the half-duplex topology matches the BACnet 3-wire (DATA+, DATA-, GND) wiring convention. The cable-invert pin simplifies field commissioning when installers cross the twisted pair. Recommended PCB practice: keep the bus traces short and isolated from switching power stages, and use a common-mode choke for long cable runs exceeding 100 m.
Recommended
Solar Inverter Daisy-Chain Communication
The ISL32455EIUZ-T suits daisy-chain communication links between photovoltaic string inverters and the gateway controller because its ±60 V bus fault tolerance directly survives the DC-bus-coupled surge events common in solar installations. The 1/8 unit load supports multi-inverter strings up to 256 nodes, which is more than enough for residential and commercial deployments. Wide ±20 V common-mode range handles the large ground-potential differences that develop across long rooftop runs. Use the part with shielded twisted-pair cabling, a 120 Ω termination at each end, and a fail-safe bias resistor network on the bus to ensure defined idle state during inverter start-up sequencing.
Recommended
Motor Drive Encoder Interface
The ISL32455EIUZ-T serves well as the encoder-feedback link between a motor drive and its controller, where the encoder cable runs alongside the motor-phase PWM cables and picks up large common-mode noise. The integrated ±20 V common-mode range rejects this noise directly, while the ±15 kV ESD protects against installer handling and field-service events. The 1 Mbps rate is more than adequate for quadrature-encoder feedback at typical motor speeds. Tie the cable-invert pin through a logic-level control so the controller can electronically swap A/B phases without board rework when commissioning bidirectional drives.
Recommended
Factory Automation Sensor Networks
The ISL32455EIUZ-T enables dense factory-floor sensor networks because the 1/8 unit load allows up to 256 nodes on a single twisted pair, eliminating the repeater cascade that classic 1/32-unit-load parts would require. The ±60 V fault protection is critical in factory environments where 24 VDC power wiring shares conduit with the communication cable. 1 Mbps data rate handles multi-sensor polling loops in tens of milliseconds. Use a star or daisy-chain topology with 120 Ω termination only at the physical bus ends; avoid mid-bus stubs longer than one-tenth of the driver rise time for 1 Mbps signalling.
Recommended
Lighting Control (DALI / DMX over RS-485)
The ISL32455EIUZ-T serves lighting-control backbone links where RS-485 transport carries DALI-2 or DMX512 frames between controllers and lighting cabinets. Its ±15 kV ESD withstands installer handling, and the ±60 V fault tolerance handles miswiring to 230 VAC mains in retrofit installations. The 1 Mbps data rate easily exceeds DMX-512's 250 kbps and supports DALI-2 multi-master configurations. Place the transceiver close to the bus connector with a 100 Ω series resistor per bus pin for added fault current limiting, and route the bus pins away from the high-current silicon-controlled rectifier dimming stages.
Recommended
Access Control / Card Reader Daisy Chain
The ISL32455EIUZ-T is a fit for RS-485 daisy-chained access-control door controllers and card readers, where each door node communicates over a single twisted pair back to a central panel. The 1 Mbps data rate handles polling of 32+ doors at sub-100 ms latency, and the 1/8 unit load supports the full door count without repeaters. ±15 kV ESD directly addresses installer handling when door panels are serviced in the field. The cable-invert pin is a useful commissioning feature when installers reverse polarity at a door location - no re-pull required.
Recommended
Recommended Products Summary
Engineering reference data for ISL32455EIUZ-T — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | ISL32455EIUZ | ISL32455EIUZ-T7A | ISL32455EIUZ-T13 | ISL32457EIUZ-T | SN65HVD75DR | ADM3485EARZ |
|---|---|---|---|---|---|---|---|
| Brand | Renesas Electronics | Renesas Electronics | Renesas Electronics | Renesas Electronics | Renesas Electronics | Texas Instruments | Analog Devices |
| Package | 8-MSOP (UZ) | 8-MSOP (UZ) - same | 8-MSOP (UZ) - same | 8-MSOP (UZ) - same | 8-MSOP (UZ) - same | 8-MSOP (UZ) - same | 8-SOIC - different footprint |
| Bus Fault Protection | ±60 V | ±60 V | ±60 V | ±60 V | ±60 V | ±18 V | ±15 V (no integrated fault) |
| Common-Mode Range | ±20 V | ±20 V | ±20 V | ±20 V | ±20 V | ±15 V | ±7 V (TIA/EIA-485 minimum) |
| Data Rate | 1 Mbps | 1 Mbps | 1 Mbps | 1 Mbps | 250 kbps | 1 Mbps | 12 Mbps |
| ESD (Bus Pins) | ±15 kV (IEC 61000-4-2) | ±15 kV | ±15 kV | ±15 kV | ±15 kV | ±16 kV HBM | ±15 kV |
| Unit Load | 1/8 (up to 256 nodes) | 1/8 | 1/8 | 1/8 | 1/8 | 1/8 | 1 unit (32 nodes max) |
| Supply Voltage | 3.0 V to 5.5 V | 3.0 V to 5.5 V | 3.0 V to 5.5 V | 3.0 V to 5.5 V | 3.0 V to 5.5 V | 3.0 V to 3.6 V (3.3V only) | 3.0 V to 3.6 V (3.3V only) |
| Cable-Invert Pin | Yes | Yes | Yes | Yes | Yes | No | No |
Key Differentiators
- Integrated ±60 V bus fault protection (vs SN65HVD75DR)
- Extended ±20 V common-mode range (vs ADM3485EARZ)
- 1/8 unit load for 256-node busses (vs ADM3485EARZ)
- Cable-invert polarity swap (vs SN65HVD75DR)
Design Notes
Route the A/Y and B/Z bus traces as a 100 Ω differential pair with matched lengths, keeping stub branches under one-tenth of the driver rise time (about 30 cm for 1 Mbps). Place a 100 Ω series resistor on each bus pin close to the IC if the cable runs exceed 10 m, to limit surge current and dampen reflections. Keep bus traces at least 3 mm away from switching power stage edges and high-current motor traces to exploit the ±15 kV ESD and ±20 V CMR ratings.
Estimated: at 5 V VCC with 1 mA quiescent current, each ISL32455EIUZ-T consumes ~5 mW quiescent and ~75 mW during a 1 Mbps, 60 Ω bus with full driver swing. Decouple VCC with a 100 nF ceramic placed within 5 mm of the VCC pin, plus a 10 µF bulk capacitor on the supply rail. The internal ±60 V fault protection works regardless of VCC state, but driver output current limiting is only active when VCC is present, so verify VCC is decoupled correctly before hot-plug events.
Do not leave the cable-invert (INV) pin floating - tie it to either VCC or GND through a 10 kΩ resistor or directly to a logic output. A floating INV pin can cause undefined polarity reversal and bus errors. Also, do not place a termination resistor on stubs - only at the two physical ends of the bus. Mid-bus stubs reflect the signal and degrade signal integrity at 1 Mbps. For multi-drop busses with more than 32 nodes, the 1/8 unit load of the ISL32455EIUZ-T is required; do not mix with classic 1-unit-load parts.
Compliance Information
RoHS compliant per Renesas product page. ESD rating ±15 kV IEC 61000-4-2 (bus pins) confirmed. Not AEC-Q100 qualified; for automotive RS-485 applications, use the ISL32455EIBZ-T automotive-grade variant.
